This invention relates in general to a frame and a carrier, that is vertically adjustable on the frame, for supporting a device or instrument. This invention specifically relates to an apparatus for supporting x-ray equipment in a vertically adjustable manner.
It is known in the medical industry to support an x-ray unit, that includes an x-ray generator and an x-ray film holder, on a carrier that is vertically adjustable with respect to a frame. It is necessary for the x-ray head to be vertically adjustable because of the different heights of patients and the different exposures that are to be taken. It is also necessary, particularly in the field of dental medicine, for the x-ray head to be rotatable with respect to the frame member so that different angles and exposures of the jaw and teeth area of a patient may be taken.
An example of a vertically adjustable x-ray head and frame member is illustrated in Brochure M-D 80/1361 Orthopantomograph 10; WSO8832. As illustrated, an x-ray unit is mounted on a carrier that is vertically adjustable with respect to a support post. The support post supports the carrier member and includes rail members upon which the carrier member is vertically adjustable. The post member has a rectangular cross-section that is hollow and includes counterweights. The counterweights are located on a pulley system and support the weight of the carrier and x-ray unit. Due to the great weight of the x-ray unit, the counterweight force must be at least 90 kilograms. Because of the construction of the cable pulley system and the weight of the x-ray unit, the apparatus provides for little tolerance and an extremely play-free guidance is provided. Moreover, due to the construction of the unit it is an extremely expensive apparatus. Furthermore, the apparatus is very large and takes up a great deal of space. Due to the weight to be supported, it is also difficult to set up the apparatus.
British Pat. No. 746,599 discloses a frame for a carrier unit comprising two spaced post members. The carrier unit is designed to be secured between the post members and is vertically adjustable therebetween. To this end, the carrier includes carriage wheels 5 that are received within guide rails 4 of the post members of the frame. Although this is a simplified construction, due to the construction of the carrier wheels and channel members it is still a relatively expensive construction. Moreover, because the wheels are received in the channel members of the frame, the channel members are relatively wide with respect to the remaining portions of the frame member. The patent fails to disclose any counterbalance member for the carrier unit in the post members.
U.S. Pat. No. 3,575,368 discloses a vertically adjustable counterbalancing x-ray unit suspension support apparatus. The apparatus includes a carrier unit, from which the x-ray unit is suspended, and an elongated frame member. The counterbalancing system is located within the frame member and comprises a compression spring and traction cable guided via a cable cam having a variable diameter, i.e., a fusee. A safety lock member is provided comprising a trapezoidal plate from which the traction cable is suspended. The edges of the trapezoidal plate are constructed so that the plate will be in locking engagement with the guide channel walls of the frame if a cable breaks.
There is a need for an improved frame and x-ray unit carrier that is vertically adjustable with respect to the frame that has an improved and simplified counterbalancing system that overcomes the disadvantages of prior art.